In practice, there are multiple possible applications in various installation sites for micromechanical components of the type discussed herein. Cited here as examples are pressure sensor elements and microphone components in which the signal detection is based on a deflection of the diaphragm structure. There are, however, also fields of application in which the deformation behavior of the diaphragm is not important, e.g., in the case of a mass flow sensor. Here, the diaphragm structure is used as a thermally decoupled carrier for the measuring shunts.
During the manufacture and installation of the component as well as during the operation of the component at the particular installation site, overload situations may occur which lead to a rupture or at least cracks in the diaphragm structure. Ruptures extend across the entire thickness of a diaphragm and often occur in the edge or clamping area of the diaphragm, since the mechanical stress is greatest in this area. In contrast thereto, cracks form only on the surface of the diaphragm structure, but do not penetrate it entirely. These cracks usually grow from the bottom to the top, i.e., from the bottom side of the diaphragm facing the cavern to the top side of the diaphragm in the component surface. Even if cracks do not necessarily result in the severance of the diaphragm, i.e., rupture, they still cause a significant signal drift of the component.
German Patent Application No. DE 197 35 666 A1 describes a micromechanical mass flow sensor element whose measuring shunt is situated on a diaphragm in the component surface. In addition to the measuring shunt, other resistor elements, which are used for rupture detection, are situated on the component surface, namely in the clamping area of the diaphragm. For this purpose, the current flow through these resistor elements is continuously monitored, since a diaphragm rupture in the clamping area results in a sudden resistance increase.